Computer Group News Editor

This paper deals with some of the problems encountered in a hybrid simulation of the motion of aerospace vehicles. These problems arise principally from the position of the analog-digital interface and the sampling, which of necessity occurs there, and introduces phase lags that can severely affect the validity of any simulation. The introduction of two redundant integrators can effectively decouple the rotational and translation loops. In this case, the high frequencies of the former can be represented in the continuous analog section, and the low frequencies of the latter can be represented in the discrete digital section. Sampling effects in loops involving digital function generation necessitate 75 to 100 samples per cycle if the damping of the simulated system is to be represented with any degree of faithfulness.